Tear gas candles are used by police and or civil defence for crowd control.  These candles are articles containing a fuse and other chemicals which when activated will disperse fine chemicals which will cause extreme eye irritation and profuse tears.

Braving Tear Gas near the AUC
Braving Tear Gas near the AUC (Photo credit: Wikipedia)

A typical candle may contain Barium Chromate, Manganese Powder, Lead Chromate, Nitrocellulose, Red Iron Oxide, Titanium Powder, Zirconium Powder, Potassium Chlorate, Sugar, Magnesium Carbonate, etc.

These articles, TEAR GAS CANDLES, are classified as toxic substances with subsidiary risk flammable solids, class 6.1/4.1, by IMDG Code.  See entry UN 1700.